The following articles concerning topics of relevance to the present invention represent the state of the art:
1. Wavelength tuning has been implemented by means of expensive individual current injection into the individual sections of the individual lasers in a semiconductor component with 10 laterally aligned 3-section DFB lasers (K. Sato et al., K-2, 13th IEEE Laser Conference in 1992 in Takamatsu). PA0 2. In an article by H. Yasaka et al., IEEE Photonics Technol. Lett. 1(4) 75 (1989), components that operate simultaneously on four different channels were presented. PA0 3. Abrupt changes in the corrugation period in the longitudinal direction of the component are known from the literature. A greater corrugation period has been achieved holographically in the central section of the laser resonator than in the side sections (M. Okai et al., IEEE J. Quantum Electron. 27, 1767 (1991)). PA0 4. To some extent, electron beam lithography makes it possible to vary the corrugation period of waveguides running side by side laterally. However, the difference between axially adjacent corrugation periods is limited to larger values in this process (C. Kaden et al., J. Vac. Sci. Technol. B 10 (6), 2g70 (1992)). Electron beam lithography is a complicated method and the recording time in electron beam lithography is very expensive. PA0 5. Tilted waveguides running on homogeneous DFB gratings make it possible to vary the corrugation period in the waveguide from that of the original DFB grating. Phase shift (Hirato Shoji; German patent 3,643,361 A1, H 01 S 3/098-C (1987)). PA0 6. The following references which use a section-by-section variation in the thickness or width of the waveguide are listed as representative of the thematic environment with regard to inducing phase shifts in a waveguide: PA0 7. Tilted waveguides were used in semiconductor laser amplifiers to reduce the end facet reflection (W. I. Way, IEEE Transac. Micr. Techn. 38,534 (1990)). PA0 8. Curved waveguides on homogeneous DFB grating fields can be used for definition of gratings with an axially varied corrugation period (see German Patent Application No. DE 42 33 500). PA0 9. W. T. Tsang et al. IEEE Photon. Technol. Lett. 5,978 (1993) proposed tilted laser waveguides, where the orientation of the gratings runs parallel to the border of the grating. This method permits a defined change in the Bragg wavelength. One disadvantage of the proposed construction is the unfavorable angle range of the angle between the waveguide and the grating lines, which is almost 90.degree.. In order to achieve a minor shift in the Bragg wavelength, a greater change in the angle must be used, but this is not advantageous and leads to fibre coupling problems with the light emitted.
A lateral widening or constriction of the waveguide width over a certain length of the longitudinal component direction is used to induce phase shifts (for example, M. Soda et al., IEEE J. Quant. Electron. QE-23,804 (1987), G. Chen et al., Appl. Phys. Lett. 60, 2586 (1992), Y. Nakano et al., IEEE J. Q. Electron. 24, 2017 (1988) or J. Kinoshita et al. IEEE J. Q. Electron. 27, 1759 (1991)). PA1 A widening of the vertical thickness of the active layer or neighboring waveguide layers over a certain length of the longitudinal component direction is used to induce phase shifts (for example, B. Broberg et al., Appl. Phys. Lett. 47, 4 (1985) or K. Kojima et al., J. Lightwave Technol. LT-3, 1048 (1985)).